As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems typically utilize a number of components formed on printed circuit boards (PCBs). As processor speeds are increasing, the available signal timing margins for signals traveling through traces or buses formed on PCBs are decreasing in a corresponding fashion. Many of the current high speed buses are differential such that symmetry plays an important role in maximizing signal margins. Many currently available PCBs use FR4 material which is made from a woven fiberglass cloth filled with epoxy resin. The dielectric constant of the materials used to manufacture PCBs is not uniform. For instance, the dielectric constant of the fiberglass is higher compared to the dielectric constant of epoxy resin. This difference in dielectric constant often causes variations in the signal propagation delay due to the positioning of the traces formed on the PCB relative to the glass fiber. This variation in signal propagation delay is problematic when more than one trace (such as a differential pair) are used to transfer data from a transmitter module to a receiver module, because signals sent from the transmitter module at the same time arrive at the receiver module at different times.
Currently FR4 panels are manufactured such that the fibers are aligned to be either parallel or perpendicular to the edge of the panel and designers prefer routing parallel to the board edges. Typical FR4 uses approximately 600 fibers per inch and typical differential pairs use 5/5/5 routing such that timing skew often occurs on every differential pair of traces. If the signal in one trace of the differential pair is delayed relative to the signal in the other trace due to the asymmetry of the dielectric material experienced by each trace, common mode signals are created and several problems can arise including lower voltage in timing margins and an increased risk of Electromagnetic Interference (EMI).